Apparatus for use in grafting articular cartilage

ABSTRACT

A device for dovetailing a wall of a cavity formed in cartilage includes a handle from which a pair of flexible blades extend, the blades having outwardly bent distal ends provided with cutting edges. A spike, fixed to the handle in a position substantially coaxial with the handle&#39;s longitudinal axis, is disposed between the blades.

This is a division of application Ser. No. 09/274,909, filed Mar. 23,1999 now U.S. Pat. No. 6,120,541.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to devices for securing articularcartilage grafts in place to facilitate successful healing of the graft.

2. Prior Art

Known methods of holding an articular cartilage graft in place involvesuturing an overlying thin membrane periosteum, a synthetic, or abiological material to the area surrounding the defect being repaired bythe graft. The sewn substance retains the graft in place while healingoccurs. However, such a suturing technique is technically difficult,time consuming and imprecise.

SUMMARY OF INVENTION

The present invention overcomes the deficiencies of the suturingtechnique just described. More particularly, the defective area beingrepaired is first removed by a drilling operation leaving a cavitywithin which the graft is to be placed. The wall of the cavity is formedto receive and retain a cap. After the graft is properly positioned, thecap is secured within the cavity in overlying relationship with thegraft so as to retain the graft in place during the healing process.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention now will be described in greater detail by reference tothe accompanying drawings, wherein:

FIG. 1 illustrates a first embodiment of a cap for retaining anarticular cartilage graft in place;

FIG. 2 is an alternative embodiment of the cap shown in FIG. 1;

FIG. 3 is a still further embodiment of an articular cartilage graftretaining device; and

FIG. 4 illustrates an instrument for preparing a cavity to receive thegraft retaining device shown in FIG. 3.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

FIGS. 1 and 2 depict an area 10 of articular cartilage which is to berepaired. A defective area in the cartilage is removed by a conventionaldrill to form a cavity 12. The wall 14 of the cavity is threaded by atap. A cap 16 is provided to be received with cavity 12. The cap is athin, disk-shaped member having a peripheral edge 18 threadedcomplementary to the thread formed in wall 14 of the cavity 12. Theupper surface 20 of cap 16 is slotted (FIG. 1) or is provided with apair of spaced holes (FIG. 2) to receive a tool which is used to screwthe cap 16 within the cavity 12.

In use, after cavity 12 is formed and its wall is tapped, an articularcartilage graft is positioned within the cavity. The cap 16 is thenscrewed into cavity 12 to overlie the graft and retain it in position.With the graft held securely in place under compression, the side of thegraft opposite cap 16 will heal to the adjacent cartilage.

An alternative type of cap is illustrated in FIG. 3. In this case, nothread is formed in cavity 12. Instead, the wall 22 of the cavity isdovetailed. A flexible disk-shaped cap 24 is dimensioned to be receivedwithin cavity 12. More particularly, the peripheral edge 26 of cap 24 isformed to be complementary with the dovetailed wall of the cavity. Inuse, and with the articular cartilage graft in place within cavity 12,the flexible cap 24 is folded and is inserted within the cavity. Whenthe cap is released, its resiliency causes it to return to its disk-likeshape whereby its peripheral edge 26 lies within the dovetailed wall 22of the cavity. Thus, the graft is retained in position during thehealing process.

An instrument suitable for forming a dovetail in the wall 22 of cavity12 is shown in FIG. 4. More particularly, a handle 28 is provided at itsdistal end with a projecting fixed spike 30 located coaxially with thelongitudinal axis of the handle. At least two flexible blades 32 and 34extend from the distal end of handle 28, the blades being secured to theperiphery of the handle. The blades are provided with outwardly bentcutting edges 36 and 38 at their extremities.

In operation, the blades are flexed inwardly from the position shown inFIG. 4 towards spike 30. The spike is used to center the knife within acavity (such as cavity 12 in FIG. 3). The blades are then releasedwhereby their resiliency causes them to move against the wall of thecavity. As handle 28 is rotated, cutting edges 36 and 38 dovetail thewall of the cavity.

The instrument just described has spike 30 and/or blades 32 and 34permanently attached to handle 28. Alternatively, at least blades 32 and34 can be removably secured to the handle by conventional means so as tobe disposable.

What is claimed is:
 1. A device for dovetailing a wall of a cavityformed in cartilage, said device comprising: a handle; at least twoflexible blades joined to, and projecting beyond, a distal end of thehandle, said blades being offset from an axis passing through the handleand having distal ends, each of which is bent outwardly in oppositedirections relative to said axis and is provided with a cutting edge onan outward side of its distal end; and a spike positioned between theblades and projecting from said distal end of the handle substantiallyalong the axis that passes through the handle; wherein the device formsa dovetail cut in cartilage when said device is rotated about the axisthat passes through the handle.